1. Field of the Invention
The present invention relates to a method and system for removing oil and gasoline from an engine.
2. Description of Related Art
It is common for small four stroke engines used in outdoor power equipment, such as lawn mowers, edgers, chippers, generators, and power washers, to be manufactured in dedicated factories that are remote from the final assembly plant. The completed engines are then periodically shipped to the final assembly plant.
Manufacturers of power equipment often require that the engines be started prior to shipment. This helps insure that the engines will work when they are ultimately assembled into the power equipment. Therefore, the engine manufacturer must include means for starting the engines prior to shipment, which entails filling the engine crankcase with oil and at least partially filling the fuel tank with gasoline.
Thereafter, in order to prevent spills and leaks, the engines must be drained of gasoline and oil before being packaged for shipment. Due to the viscosity of oil and the speed at which the engines must be drained, it has heretofore proven necessary to use a pump to evacuate oil and gasoline from the engines. The pumped-out oil and gasoline is directed toward an oil recovery tank and a gas recovery tank, respectively, for recycling and/or re-use.
In the past, oil and gas have been pumped out of the engine by pumps that are in the flow line between the crankcase and the oil recovery tank, in the case of oil, or in the flow line between the fuel tank and the gas recovery tank, in the case of gasoline. However, this prior art method and system has proven unreliable as the pumps have required relatively frequent maintenance and repair. It is believed that oil and gasoline damage the pump seals, resulting in leakage problems, frequent repair, and excessive downtime.
Therefore, there exists a need in the art for a method and system for quickly and reliably removing oil and gasoline from an engine.
The present invention is directed toward an improved method and system for removing oil and gasoline from an engine.
In accordance with the present invention, a system for removing liquid from an engine includes a first liquid storage tank, a second liquid storage tank, a return tank, a vacuum source, and a pressurized air source. Fluid communication between the tanks and the pressure and vacuum sources is controlled by a controller that actuates valves in response to sensed liquid levels in the first and second liquid storage tanks.
In further accordance with the present invention, a first conduit, which is adapted for insertion into an engine reservoir that contains liquid to be removed, provides liquid to the first liquid storage tank. A second conduit extends between and fluidly interconnects the first and second liquid storage tanks. A first control valve is disposed in the second conduit and serves to control fluid communication therethrough.
In further accordance with the present invention, the vacuum source establishes a vacuum or sub-atmospheric pressure in the first and second liquid storage tanks while the pressurized air source selectively communicates pressurized or over-atmospheric pressure air to the second liquid storage tank. Preferably, vacuum is continuously provided to the first liquid storage tank while pressurized air and vacuum are supplied to the second liquid storage tank in a mutually exclusive fashion.
In accordance with other aspects of the invention, sensors are provided for sensing liquid levels in the first and second liquid storage tanks. Also, a controller actuates the first and second valves and controls communication of pressurized air from said pressure source, in response to sensed liquid levels.
The present invention also teaches a method for removing liquids from an engine reservoir. The method includes communicating vacuum to the first and second liquid storage tanks and inserting a nozzle of a first conduit into the engine reservoir. The first conduit includes a nozzle valve for controlling communication of liquid from the engine reservoir to the first liquid storage tank via the first conduit.
In further accordance with the method, a first control valve is placed in a first position to permit liquid to flow from the first liquid storage tank to the second liquid storage tank. The level of liquid in the first and second liquid storage tanks is monitored.
In further accordance with the inventive method, when the liquid level in the second liquid storage tank reaches a first predetermined level, the first control valve is placed in a second position to prevent liquid flow from the first liquid storage tank to the second liquid storage tank, communication of vacuum sub-atmospheric pressure air to the second liquid storage tank is discontinued, and pressurized or over-atmospheric pressure air is communicated to the second liquid storage tank to force liquid therein to flow through the third conduit toward the return tank.
In accordance with another aspect of the method, when the liquid level in one of the first and second liquid storage tanks reaches a second predetermined level, the communication of over-atmospheric pressure air to the second liquid storage tank is discontinued, communication of sub-atmospheric pressure air to the second liquid storage tank is reestablished, and the first control valve is returned to the first position to permit liquid to flow from the first liquid storage tank to the second liquid storage tank.